Discontinued Operations (Details) (USD $)	12 Months Ended					12 Months Ended		1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2012 property	Dec. 31, 2011	Dec. 31, 2010	Feb. 29, 2012	Apr. 30, 2010	Dec. 31, 2012 Shopping Centers [Member] property	Dec. 31, 2011 Shopping Centers [Member] property	Nov. 30, 2012 Industrial Properties [Member] property	Dec. 31, 2012 Industrial Properties [Member] property	Dec. 31, 2011 Industrial Properties [Member] property	May 31, 2012 Wholly Owned Properties [Member]	Dec. 31, 2012 Arizona [Member] property	Dec. 31, 2011 Arizona [Member] Shopping Centers [Member] property	Dec. 31, 2012 Colorado [Member] property	Dec. 31, 2012 Florida [Member] property	Dec. 31, 2011 Florida [Member] Shopping Centers [Member] property	Dec. 31, 2012 Georgia [Member] property	Dec. 31, 2011 Georgia [Member] Industrial Properties [Member] property	Dec. 31, 2012 Illinois [Member] property	Dec. 31, 2011 Illinois [Member] Shopping Centers [Member] property	Dec. 31, 2012 Kansas [Member] property	Dec. 31, 2011 Kansas [Member] Shopping Centers [Member] property	Dec. 31, 2012 Louisiana [Member] property	Dec. 31, 2012 Maine [Member] property	Dec. 31, 2012 North Carolina [Member] property	Dec. 31, 2011 North Carolina [Member] Shopping Centers [Member] property	Dec. 31, 2012 Oklahoma [Member] property	Dec. 31, 2012 Tennessee [Member] property	Dec. 31, 2012 Texas [Member] property	Dec. 31, 2011 Texas [Member] Shopping Centers [Member] property	Dec. 31, 2011 Texas [Member] Industrial Properties [Member]	Dec. 31, 2012 Virginia [Member] property
Discontinued Operations [Line Items]
Number of operating properties sold						27	8	9	54	3	52	1		2	6	1	6	2	1		1	1	2	1	3	1	1	1	55	5	1	2
Ownership percentage in joint ventures	75.00%			47.80%	50.00%
Number of properties reclassified from held for sale						2
Property reclassified from held for sale, net	$ 10,000,000
Operating (loss) income reclassified from discontinued operations		(100,000)	800,000
Number of properties held for sale	0						7						1			1				1						1				3
Property held for sale, net	0	73,241,000
Gross property included in discontinued operations		673,800,000
Accumulated depreciation for property included in discontinued operations		$ 156,200,000
Interest expense allocated to discontinued operations	We do not allocate other consolidated interest to discontinued operations because the interest savings to be realized from the proceeds of the sale of these operations is not material